Robust wire-based supercapacitors based on hierarchical Α-MoO₃ nanosheet arrays with well-aligned laminated structure

Due to their high pseudocapacitance and laminated structure, α-MoO₃ nanosheets have been considered as one of the promising electrode materials of energy storage devices. In this work, hierarchical α-MoO₃ nanosheet arrays have been in-situ grown on Mo wires (MoO₃-Mo wires) via one-step calcination in air. The obtained MoO₃-Mo wires possess well aligned laminated structure, which will benefit intercalation of Li-ion into the electrodes. Thus, a type of Li-ion electrolyte was applied in the assembled wire-based supercapacitors (WSCs). Electrochemical tests showed that the MoO₃-Mo single wire electrodes can exhibit high capacitance (7.68 mF cm⁻¹ at 2 mV s⁻¹) and excellent cycling stability (nearly 100% after 4000 cycles). Moreover, series of optimization tries indicated that the laminated structure of MoO₃ nanosheet arrays can be well tuned by calcination temperature and time, accordingly resulting in the optimized electrochemical performance. Furthermore, the assembled all-solid state symmetrical WSCs based on MoO₃-Mo wires showed high energy density (∼1.04 mW h cm⁻³), high cycling stability, and good flexibility.